#!/usr/bin/env python
# -*- coding:utf-8 -*-
import threading

def do(event):
    print 'start'
    event.wait()
    print 'execute'

event_obj = threading.Event()
for i in range(10):
    t = threading.Thread(target=do, args=(event_obj,))
    t.start()

event_obj.clear()
inp = raw_input('input:')
if inp == 'true':
    event_obj.set()